Locomotor training using body weight support and a treadmill as a therapeutic modality for the rehabilitation of walking post-stroke is being rapidly adopted into clinical practice. A recent Cohrane review highlighted the urgent need for a well-designed trial to determine the effectiveness of this intervention. The proposed objective of the Locomotor Experience Applied Post-Stroke (LEAPS) trial is to conduct a 5 year, phase-Ill, single-blind, multi-site (5 clinical sites) randomized clinical trial (RCT) to assess if there is a difference in the proportion of subjects who successfully recover walking ability between a specialized locomotor training program (LTP) that includes use of body weight support and a treadmill as a rehabilitation modality provided 2 months post-stroke (LTP-early) or 6 months post-stroke (LTP-late) and a non-specific, low intensity exercise (control) intervention. The study is designed to be a definitive RCT with the primary outcome being successful recovery of walking (achieving a 0.4 m/s gait speed or greater for persons with initial severe gait impairment (<0.4 m/s) or as having achieved a 0.8 m/s gait speed or greater for persons with initial moderate gait impairment (>0.4 m/s - <0.8 m/s) at 1 year post-stroke. We will also determine if the timing of LTP delivery (early vs. late) affects the improvement in gait speed at 1 year and whether initial locomotor impairment severity interacts with the timing of LTP delivery. The LTP and control interventions will be delivered for 36 sessions over 12 weeks. We will recruit 400 adults, age 18 or older, within 30 days poststroke onset with moderate to severe walking ability. After screening and baseline assessment, subjects will be stratified by baseline locomotor impairment severity as determined by overground walking speed and randomly assigned to 1 of 3 groups: (a) LTP-Early;(b) LTP-Late or (c) Control. The effect of number of treatment sessions will be determined by changes in gait speed taken pre-treatment, post-12, post-24, and post-36 sessions. Our ultimate goal is to provide evidence to guide post-stroke rehabilitation practice and reduce disability in persons post-stroke.